Bottleneck 0.6.0

First release candidate of Bottleneck 0.6

Four new functions, single source dist, bug fixes.

rankdata and nanrankdata crashed on win64

argpartsort, nanargmin, nanargmax returned wrong dtype on win64.

32/64 bit clean up.

Second beta of Bottleneck 0.5.0.

Beta release of 0.5.0

median() and nanmedian() bug fix release

Bug fix release.